The present invention relates to an oxygen gas analyzer using a solid electrolyte.
FIG. 1 illustrates the general structure of an oxygen concentration cell (with zirconia or the like) constituting a sensor of an oxygen gas analyzer, in which 11 denotes a solid electrolyte forming a partition wall between two sides A and B. Electrode films 12a and 12b of platinum or the like are formed on the surfaces of the partition wall 11, and leadwires 14a and 14b are connected directly to the electrode films 12a and 12b, respectively. When a partial gas pressure introduces an unknown object gas to one side B of the oxygen concentration cell while a partial oxygen pressure introduces a standard gas to the other side A, then a voltage E expressed by the following equation is generated between the electrode films 12a and 12b: ##EQU1## in which
Ti: transport number of oxygen ions
R: gas constant
T: absolute temperature
n: number of electrons contributing to reaction
F: Faraday constant
Px: partial oxygen pressure representative of object gas to be analyzed
Ps: partial oxygen pressure representative of standard gas
Therefore, the partial oxygen pressure representative of the object gas to be analyzed, that is, the concentration of the oxygen gas, can be obtained through measurement of the generated voltage E by the use of a voltmeter or the like via the leadwires 14a and 14b. In the known oxygen concentration cell of this type, it has been customary heretofore that the electrode films 12a and 12b are attached by baking to the partition wall 11. For this reason, rapid interconversion between the oxygen gas and the oxygen ions is rendered impossible thereby preventing the cell from attaining a short response time.
Moreover, according to the prior techniques, the leadwires 14a and 14b are connected either directly to the electrode films 12a and 12b or to platinum plates bonded to the electrode films, as shown in FIG. 1. The former method has a disadvantage of insufficiency in the mechanical strength against an external force or the like and may often cause an incomplete electrical connection. Although the latter method is capable of solving the problems observed in the former, it still fails in meeting the entire requirements thoroughly due to irregularity in the bonding strength.